Grinding fixture



Filed March 22, 1927 3 Sheets-Sheet l mlllllwggf WITNESS July 8, 1930.

A. MCANDREW 1,770,318

GRINDING FIXTURE Filed March 22, i927 s sheets-sheet 2 INVENTOR WITNESS I ATTORNEY.

' July s, 1930.

A. McANDREw v 1,770,318

GRINDING FIXTURE Filed March 22,. 1927 3 Sheets-Sheet 3 mmllllllilllll V\ m Ill INVENTR A.M"427afnm{ wlTfblEsfs QHMN y EY ATTORNEY `Patented July8, n

i 'UNETEfDiS-T ANDREW MCANDREW, on Nonin LITTLE nooxfnitxnnsaa AssIGofIt y To WILLIAM zr. Hymns, on'NoR'rII LITTLE Boex, ,nRKAjNsAsmf e y GRINDIG nrxgrUREY n.

Appncatiomea March 22, 19.27,'y serial n0.'1'7"7,3154. I

i' This invention relates to grinders and more n grinding millingformed of a plurality of connected, yetdis-fv tinct, cutting edges Which together approximate a curve and Which' havein this case defined as the radius vofthe teeth.

A primary Vobject of the invention is to provide a device capable of grinding the face, radius and sides of both large and smallfmilling cutters and backing 0E tov proper clearance in one operation.

grinder that it Will accurately grind a perfect radius or arc of any'size.v Y

Another object is to providea grinding unit of this character Which is very compact and can be made of ditlerent sizes andused on any standard full universal or plain grind# ing machine.

In carrying out these objects the invention Y is susceptibleof a Wide range of modifica-` tions Without departing from the vspirit or sacrificing any of the advantages ot the` i claimed invent-ion; there beingshovvn in the drawings for illustrative purposes certain T preferred and practical forms, in which FigurelV representsa side elevation of a grinding fixture constructed in accordance with this invention. shown in use, f

Fig. 2 is a similar vieW With thervixture in a position at right angles to'that shovvn in Fig. l, f Fig. 3 is a horizontal lsection with parts broken out and in section,

Fig. 4 is a detail transverse section of the base member, l n f Another object is to so construct such a .A

Fig. is a det-ail 4showing the path-of the gndllg Wheel', and: f f l Fig. 6 is a vertical sectlo n theiknee-vvithi vparts' ofits support-broken avvay.V

f In the embodiment illustrated a baseiplater` lis shown adapted to be fastened tothe Ina-'1 chine plate,l not y`shovvn,fvvhich 'carries theV original cross 'and longitudinallfeeds orf-the-I .y

machine. Thisbase plate l is shown fcir-yv` cular in `form withl laterallyV extending attaching lugs. or rears V'2' arranged at diametri'- cally opposite points and havin'gopeny slotsf v therein [to receive .i the .fastening elements' 41j This b'ase'member l has an annulapgl-Qovef v extendingaround its upper tacernear itsL-o periphery and ywhich is inverted--Tshapedlin crosssectionand'designed toreceive adi justablestops in theform oibol'ts.- *Thesev stops-6 are insertable throughanopening 7.v

'A rotary motion member 1.0 is mounted on' 65 the base 1 andis used for the grinding of.' the radius-or a'rc'of:the"cutterfteeth, 'said `arc l being locatedfbetweenthe radial or peripheralY members or legs of said teeth,` `This member l()` has on itsupper face a trans-"f versely extending undercut cleat 'lOa'adapt'edf to slide-.in correspondinglyshaped seat 11h*` formed transversely Vin thelower face 'oet al superposed plate 11. This plate 'llfisjvadl' justedby-scrjew 12 to locate the cutteron either-.tl'ie right or left of the center as may be desired, a handle lfor operatingfscrew12 being shownat 12rin Figs. 2 and 3. [A plate i3 isjmountedl on top of plate' 11j and arranged at fromv the cleatv or gib 10a* on the rotary'member 10 and is adapted to slide on platell on a transverseundercut .i y

'device is applied. The uprightmember'lal of this knee 15 is ,bored above its center at lan angle off30 toa perfectball socket-516190- arbor.

litted in socket 16 and is retained in place by a locking plate or collar 20, held by four cap screws a. This lock plate is iitted to the rear face ofthe knee 15 and is bored on an angle, as shown at 21, to provide ample scope for the arbor 17 when assembled. VWhen the degree required for angles of various cutters is determined, the arbor 17 can be locked to the kneex15 by plate 2O and the cutter. 25 is ready for grinding since it rotates freely on .l

the arbor 17, a collar 19 on said arbor forming an' abutment for the cutter.

Means for arresting the motion of the cutter While grinding, is shown in the form of a finger 22, which is placed under the blade of the cutter being ground, to hold it in position While grinding. This finger 22' may beV placed either on theV fixture or on the head of the grinding machine. When the ball V1S is setY tothe degree required to properly position the cutter to be carriedy thereby, it is firm- .ly locked and the cutter is adjusted to the finger ,by'turning on the arbor 17 since the cutter is not driven on but heldby a Well seated bushing placedon the arbor. The path of thel grinding Wheel 3() relative to a cutterV tooth or blade 26, is shown in Fig. 5 and the grinding of the cutter is begun on the side of the point `Where the radius or arc begins vwhich is determined by the stop 24v on the longitudinal movement of thegrinding machine table 23. When this stop is reached the rotary member 10 comes into play and is moved to causetheblade to engage the grinding Wheel 30 until itreaches theend of its radius or arc, Whichis governed by the stop 6 on base 1 after Which the face of the cutter is ground by the longitudinal movement of the machine table. This operation completes the grinding of one blade 26 of the cutter 25. Thel cutter is then swung on the arbor 17 to bring the next blade in position, the face or leg 2621 of the cutter beingfirst groundthenv the radius or arc 26b and last the side or leg26c, and so onuntil all of the teeth or blades of the cutter are finished. With the cutter 25 shown, Whenv the blades on one half are ground the cutter is removed from the arbor and turnedv around andthe operation above described is repeated. The above descriptionV applies to` staggeredVK helical cutters which continue across t-heface andcan be ground in one continuous operat-1on,th1s, of course, applies to mediate itsr ends-andfitting4 said socket, and*y means#forlockingtsaid ball within said: socket 

